A variety of conventional light sources such as fluorescent lamps, neon lamps and halogen lamps have preoccupied in the market of flood lamps, landscape lamps, and advertising lamps. However, light emitting diodes (LEDs) are in the spotlight of consumers as light sources in the lamp market in recent years. The reason why LEDs are getting the spotlight in the field of light sources is due to the device characteristics of the LEDs.
The conventional light sources that emit light using mercury are not environment-friendly, but the LEDs that emit light without using mercury are environment-friendly. In addition, the LEDs consume less electric power, to thereby save a maintenance cost. Further, the LEDs have the characteristics of longer life expectancy, more excellent durability, and stronger solidity than the conventional light sources.
In addition, the LEDs are gradually getting better in the electrical features of brightness and luminous efficiency. The LEDs are also driven at low voltage, to thus cause no risk of electric shock. As a result, the LEDs are being widely used with increasing speed. In particular, the LEDs are increasingly applied in the illumination field of buildings and landscapes due to an easy applications and brilliant lighting effects of the LEDs.
Considering these points of view, lighting apparatuses using light emitting diodes (LEDs) have been recently proposed as light sources. Light emitting diodes of low power consumption and with high brightness have been developed due to the technological development, and have been gradually spread in use. In the case of the high brightness light emitting diodes, light rays that are emitted from the high brightness light emitting diodes have stronger candle power. Accordingly, a light emitting diode chip containing a number of light emitting diodes is packaged so that light rays that are emitted from the light emitting diode chip are dispersed to irradiate a wider area. As a result, it is possible to use the light emitting diode chip whose light emitting ranges are divided into for example, 12° lens, 25° lens, 30° lens, 45° lens, reflector and so on.
The conventional LED lighting apparatus using these LEDs includes: a bar-shaped housing with a certain length; a printed circuit board (PCB) of a certain length that is installed in the inside of the housing; a number of light emitting diodes that are installed on the printed circuit board; and an electric power supply that supplies electric power with the LEDs.
The conventional bar-shaped LED lighting apparatus is disclosed as an LED landscape lighting apparatus in Korean Patent No. 10-0834973 in which only a number of bar-shaped lighting units are used with no separate lighting structure, to thereby perform a lighting situation of a bent state, and the number of the bar-shaped lighting units can be easily installed on stepped walls of a building.
The LED landscape lighting apparatus includes: a connecting member body having a certain length; a connecting member on both sides of which circular protrusions are respectively formed along the lengthy direction of the connecting member body; a number of lighting units each of which has a certain length, and both sides of which are respectively fitted into the protrusions of the connecting member so as to be rotated; and a number of light emitting modules that are respectively disposed in the lighting units and receive electric power from an external power source to thus emit light.
However, the LED landscape lighting apparatus has a problem of having no effective heat radiation because the light emitting module including a light emitting diode, a printed circuit board (PCB), and a controller is disposed in the unit body of the lighting unit, and end covers are combined on both sides of the unit body in order to protect the light emitting module, with a result that the inner portion of the unit body is maintained to be in a sealed state.
In other words, the LED landscape lighting apparatus has the difficulty in efficiently diffusing heat emitted from a number of high brightness light emitting diodes to the outside. As a result, the LED landscape lighting apparatus may cause problems that degrade light emission efficiency by the heat, as well as that damages parts of the LED landscape lighting apparatus.
In addition, Korean Patent No. 10-0903305 discloses a fluorescent lamp type LED lighting apparatus in which a printed circuit board (PCB) playing a role of an electric power source is housed in the inside of a rectangular vessel-shaped main body on the side of which a number of heat radiation fins are formed, both sides of the main body are sealingly combined by brackets, a bar-shaped LED and lens portion is mounted in an LED accommodation portion that is formed at the upper side of the main body, and a cover that is formed in the form of covering the LED and lens portion in order to protect the LED and lens portion is combined at the uppermost side of the main body.
However, since the LED lighting apparatus disclosed in the Korean Patent No. 10-0903305 employs a structure of sealing the inner portion of the main body with the brackets, heat that is diffused downwards from the LED and lens portion is not effectively radiated.
Meanwhile, in a well-known bar-shaped flood lamp, light emitting diodes are mounted on metal printed circuit board located at upper part of heat radiation housing. A number of heat radiation fins are perpendicularly extended from the metal printed circuit board. However, such a heat radiation fin structure has a problem of decreasing a heat radiation effect. As described above, in the case that a power supply is set inside of the heat radiation unit, the heat radiation unit need to be sealed. Accordingly, heat that is generated in the inside of the unit may not be efficiently discharged out.